Question

How are the formulas for the circumference of a circle and area of a circle derived?

Answer 1

they are derived using calculus.

Answer 2

@TrojanPoem do you think u could help me

Answer 3

See this: http://math.stackexchange.com/questions/187987/calculus-proof-for-the-area-of-a-circle

Rajesh K Singh answer is what you're looking for

for the circumference once you 've proved the area

derive it with respect to r to get the circumference .